I'm questioning the oil level indicator on my trans dipstick. I'm not sure if it's the correct dipstick for a 1971 426 Hemi trans as I'm told they are different from others. So, if I drop the trans pan for a filter swap only, how much trans fluid should I be expected to put in?

There's too many variables to expect a valid answer based on other people's experience. Drop the pan and visually look at the bottom of the dipstick. The full mark (at operating temp in neutral) should be about an inch above the the rail that the pan bolts to. Add whatever it takes and make sure the trans is HOT before you top it off. Temp makes a significant difference on the dipstick. There is no exact level for trans fluid in a 727. You want it above the filter at all times but not overfilled. That can cause aeration or blow fluid out the vent.

Standard capacity for a 727 with a stock pan is about 5 quarts.
If you are gonna change the filter and fluid go ahead and drain the convertor if it has a drain plug. It is behind the flat shield, behind the oil pan, on the transmission housing face. You may have to rotate the engine to find the small drain plug. Not all torque convertors have them today but the factory did back in 1970.

Draining the torque convertor will add between 2 and 4 quarts to the 5 above depending on the size.

I can't find a good picture but the dipstick should extend into the transmission about 3/4 of inch or so. Here is a small block tube for reference. The level for a 727 will be the same for all engine types.

The difference in a Hemi Dipstick should be the shape of the tube not the depth of the fluid.

John Kunkel is the resident Auto Transmission expert and may have better advice/pics.

I can answer the question.
If you buy 6 quarts, you'll need 8.
If you buy 10 quarts you'll need 5
As mentioned there are too many variables to give an accurate answer.

Good picture. I guess the question is if all dipsticks protrude past the tube the same distance. I understand '71 Hemi auto transmissions are a bunch of new and old hemi parts pulled together.

Yes the fluid level in all 727 transmissions is the same. It always will be above the filter and below the rotating assembly. About 1" above the pan rail but that is a gross estimate. Don't take that to be an exact dimension.

Differences in capacity is based on the size of the torque convertor and depth of the pan if it has been changed. All factory passenger car 727 pans were the same big or small block. A common race trick is to add a deeper pan and then extend the filter down into the deeper fluid but yours is stock so 5 quarts + convertor is a good estimate.

I judge by your other post you are trying to make sure the dipstick is correct but if it truly about the fluid change when I add the fluid add up to the full mark. Without moving the car I slowly run it trough all the gears and check the level again. Since it will be cold I add to the add mark. Let the car fully warm up while sitting in neutral or gently driving. Neutral pumps the fluid and park does not on a stock 727. Run it through the gears and add up to the hot mark.


That is my system but others may have a better system for them.


If this is about the dipstick being correct I wish I had a picture of the dipstick extending into the transmission from inside the pan but I don't. This is as good as I could find.

GTX - The problem is it's a '71 Hemi trans. I understand hemi auto's holds 6 quarts but not because the pan is deeper which adds to the confusion. My pan looks exactly like the pan on my 440, no difference in depth so where does the other quart go? The extra hemi cooler doesn't look like it can carry another quart but maybe 1/2 quart? And from other posts, the dipstick is a different on a 70-71 hemi vs 67-69. If I could empty the entire system, then add 6 quarts, then mark the stick wherever the level is would solve the problem but getting everything out sounds like a lot of work.

I get a better sense of where you are going from now.

There are lots of areas that fluid will hide from the cooler, to the torque convertor to the pistons and clutch packs etc. Easy to loose a quart in all the little places but all the transmissions will keep the same level relative to the case.

If you can find someone who has their pan off and see how far it is from the pan rail to the tip, and from the tip to the hot mark you can compare it to yours.

That picture shows you how far the tip extends into the pan. If yours is much different than that I would worry.

Another method is to measure the dipstick relative to the end of the tube. They should all be the same because the tubes extend into the case the same amount when installed.

I will try to dig up a tube and dipstick in the next couple days.

I hope that was not my post, I misread the trans discussion and posted about the Oil pan stick. According to the parts book, the hemi trans dipstick was the same part number 66-71. The tube changed in 69.

DS - There is a 4202951 part number stamped on my dipstick just below the rivets. Do I have the correct dipstick?

The parts book say 2538349 from 66-71 for the Hemi stick. Not sure if yours is a Mopar performance part number?

Google "4202951 dipstick" for more confusion

I find it had to believe that Mopar would rivet a dipstick on production. Is there really no one with a hemi auto with original dipstick to give the measurements? Mine is a 4speed so no help.

I had a suspicion but had to confirm it. I never realized that all the dipsticks are the same, except the Hemi.

This picture is from a unmolested 1970 -440/727, race 1974-440/727 and an all original 74-318/904.

The 70/71 parts book lists 1 part number for all engines EXCEPT the 426 but I think you may know that already.

If your dipstick number is correct then it isn't for a Hemi but the fact it has rivets may indicate somebody modified it.

The dimensions for thee dipsticks are 18" from the staked spot under the seal to the tip. About 18-3/4 from the top of the seal to the tip and about 21.5 overall.

At the end of it all I think you will need to measure how far the stick extends into the pan and compare it to any other 727 transmission.

I did a little more checking since I was home near my parts books and all the Hemi's from 67 to 71 used the same part number dipstick.

I believe 68 Jim posted his dipstick was in the neighborhood of 14" so the hemi stick is shorter than other engines.

Excellent Info GTX. Thanks. I must say though, the stick section cut and rivets look factory.

Funny that on my dipstick, there is an "M" stamped after the part number. M for Modified?? My '71 Hemi carbs are actually 1970 carbs modified for the 1971 Hemi with an "M" stamped in front of the part number. I understand that this is factory correct for a '71 Hemi.

At least one of my dipsticks had an M stamped on it.

Maybe it's a stamp from whomever made it or?

None of mine had Rivets though. It is common on some manufacturers factory dipsticks to have rivets but I can't recall one way or the other any from Mopar back in the 70's so I can't say for sure.

That is what I said earlier. The stick is the same, the tube chanced as they went from bolt on to press on tube. Isn't M mopar performance part numbers.

DS - Here is the dipstick with the part number and the "M". The M might not even be associated with the part number.